印迹与交联壳聚糖吸附水中微量Cr(Ⅵ)的对比试验研究

Comparing the Adsorption Properties of Chromium(Ⅵ) onto Crosslinked Chitosan and Impriting Chitosan

本研究以壳聚糖为原料,戊二醛为交联剂,分别采用直接交联的方法和分子印迹技术制备交联壳聚糖和Cr(Ⅵ)印迹壳聚糖,并对这两种吸附剂对Cr(Ⅵ)的吸附性能进行了研究,考察了pH、反应时间、吸附剂投加量、Cr(Ⅵ)初始浓度、温度对Cr(Ⅵ)去除率的影响.实验结果表明:酸性环境有利于壳聚糖类吸附剂对Cr(Ⅵ)的吸附,pH为6.0时吸附效果最佳.交联壳聚糖和印迹壳聚糖对Cr(Ⅵ)的吸附速率在前20 min较快,90 min即可达到吸附平衡.对30 mg/L的Cr(Ⅵ)溶液,交联壳聚糖与印迹壳聚糖对Cr(Ⅵ)的去除率随投加量增加而增加,在投加量为3.5 g/L时,对Cr(Ⅵ)的去除率最高可达到92.4%和97.8%.相同实验条件下,印迹壳聚糖对Cr(Ⅵ)的吸附较交联壳聚糖有明显提高,其幅度最高可达7.3%.

In this study,using chitosan as raw materials,glutaraldehyde as crosslinker,direct cross-linking method and molecular imprinting technique were applied to prepare crosslinked chitosan and Cr（Ⅵ） imprinting chitosan.The adsorption properties of Cr（Ⅵ） on these two absorbents were explored.The effect of pH,reaction time,adsorbent＇s dosage,the initial concentration of Cr（Ⅵ） and temperature on Cr（Ⅵ） removal was studied.The experimental results showed that Cr（Ⅵ） was favaroble to be adsorbed by these two adsortents in acid conditions.Optimum biosorption was observed when the solution pH was 6.0.The adsorption rate was high in the earlier 20 min,and the adsorption equilibrium was established in about 90 min.For treating 30 mg/L of Cr（Ⅵ） solution,the percentage removal of Cr（Ⅵ） by these two adsortents increased with the increasing of the adsortent dosage.When the adsorbents dosage was 3.5 g/L,the maximum percentage reomoval of Cr（Ⅵ） by crosslinked chitosan and imprinting chitosan reached 92.4% and 97.8%,respectively.Under the same conditions,compared with crosslinked chitosan,the imprinting chitosan can adsorb more Cr（Ⅵ） ions,and the removal efficient of Cr（Ⅵ） was enhanced up to 7.3%.